Parallelogram-type pantograph



June 30, 1931. p KAPPLER 1,811,940

PARALLELOGRAM TYPE PANTOGRAPH' Filed Aug. 30 1929 V: j s 5i 9- 5 gs Patented June 30, 1931 i UNITED STATES PATENT OFFICE PAUL KKPPLER, F DRESDEN, GERMANY PARALLELOGRAM-TYPE PANTOGRAPH Application filed August 30, 1929, Serial No. 389,366, and in Germany April 10, 1929.

The present invention relates to pantoits eccentric bushes and Fig. 3 is a cross-secgraphs for machines, apparatus and instr'utional view through the parts shown in Fig. ments employing pantographs or like en- 2 on line 33. larging and reducing apparatus, or copying The link system 1, 2, 3 and 4 is rotatably 5' apparatus and has for its object to provide mounted on a fixed pole or pivot in' a s'up- 5b a greater ratio between the movements of porting block 5. Thetracing point or pin the tracing point and the stylus, work tool 6 which e. g. traces the pattern Z is caror microscope and also to attain greater ac-- riedvat the end of a rod 9 whilst a microcuracy in the reduction or enlargement, parscope is indicated at 7 e. g. for viewing the 10 ticularly in apparatus for viewing the work work tool of a machine. In place of the 0 tool of machines such as lathes, grinding mlcloscope there may be a reproducing machines, laners, gear wheel milling mastylus 01 the spindle Of a I'QPI'OdLlClHg tOOl. chines and the like. According to the present invention and as In the ordinary construction of pantoshown in Fig. 2, the block 5 which serves as graphs with a relatively large reduction the fixed pole or pivot has a large internal 65 or enlargement, the fixed pole or pivot, one bore 5' in which a bush 4' is rotatably mount of the link pivots and the stylus, tool spined, the bush 4: being fixed by screws 4a or dle or microscope are so close together that the like to the link 4. The bush 4' has an a firm support cannot be obtained. Thereeccentric bore 4 whose axis coincides with fore in engraving machines the expedient is the point 8 in Fig. 1. In the eccentric bore 70 adopted of arranging the pivots in different 4- is rotatably mounted a bush 3., fixed by planes, e. g. the fixed pole or pivot is arscrews 3a or the like to the link 3. J The bush ranged above and the engraving tool or tool 3 has an eccentric bore 3" whose axis cospindle is arranged below the pantograph incides with the point 7 and in the bore 3" is system. It is obvious that the accuracy of mounted atool, stylus or other reproducing the apparatus is thus endangered owing to instrument, here illustrated as a microscope the difficulty of manufacture and manipula- 10,for viewing a machine tool. It will be tion as well as owing to the side forces which observed that in this manner a firm.mo untoccur. Thus the reduction or enlargement ing and support for the work tool or microwhich can be attained isvery limited. scope 10 is ensured. The distance from the Alt these drawbacks are overcome accordcentre of the bore 5' to the centre of the ing to the present invention by constructeccentric bore 4: represents the distance being the axes of the fixed pole, link pivot and tween the points 5 and 8 in Fig. 1 and the stylus, tool spindle or microscope (which distance from the centre of the bush 3 to the 35 ordinarily are close together) in the form of centre of the eccentric bore 3" represents the nested bushes with eccentric bores in such distance between the points 8 and 7 in Fig. a manner that the pivot pin of the pivoted 1. The eccentricity of the bushes 3' and 4' link of the parallelogram encloses or emcan be accurately measured and made to braces the adjacent link 'oint of the paralwithin a few thousandths of a millimetre.

lelogram and the'said li joint encloses or The greater the reduction or enlargement to embraces the stylus or reducing pen, rebe made by the pantograph, the smallerwill producing tool, viewing microscope or the the eccentricity of the bushes be made, so like. that the greatest reduction or enlargement ()ne manner of carrying out'the invention can-be obtained without diflicultiy. p

5- is illustrated in the accompanying drawing a The bearing faces of the bus es may also o by way of example. v be fitted with or constructed as ball or roller Figure 1 is a diagrammatic plan view of bearings. a pantograph. Variation of the reduction or enlargemen Fig. 2 is an elevation showing a practical can be obtained in the construction accordemotion of the fixed pole or pivot with ing to the present invention by; correspondm ingly varying the lengths of the links 2 and y 4 and of the arm 9 (by substituting longer or shorter links) or by replacing the bushes 3 and 4: by bushes of different eccentricity. It is also conceivable that the eccentricity of the bushes might be variable and adjustable by means of wedges or the like.

The invention can also be employed with machines, apparatus or instruments in which the reproducing tool, stylus or the like is guided by a plurality of pantographs. The bushes may. also be each adjustable in the direct-ion of their centres.

Claims:

1. In a pantograph of the parallelogram type, a fixed pivot for one of the links of the parallelogram comprising a member attached to said link and rotatably embracing the adjacent link joint of the parallelogram, said joint having its axis of rotation eccentric to, but within, said member and comprising a member which rotatably embraces a reproducing element, eccentric to its axis of rotation.

2. A pantograph comprising a linkjointed parallelogram, .one link joint of which comprises inner and outer relatively rotatable bushes in eccentric relation to each other, each bush being attached to one link of the parallelogram, a reproducing element eccentrically mounted within the inner bush, and a bearing within which the outer bush is rotatably mounted.

3. A pantograph comprising a system of links jointed to form a parallelogram, one of said links carrying a tracing point, and one of the link joints compring inner and outer cylindrical members attached to adjacent links, the inner member being rotatable within an eccentric aperture in the outer member, a reproducing instrument eccentrically mounted within the inner mem her, and a stationary bearing encircling the outer member.

4. A pantograph comprising a link-jointed parallelogram, a link joint of which comprises inner and outer relatively rotatable bushings, each attached to one link of the parallelogram, areproducing element mountedwithin the inner bushing, and a.

bearing supporting the outer bushing for" rotary movement.

5. A pantograph comprising a system of links jointed to form a parallelogram, one of the link joints comprising inner and outer cylindri'al members attached to adjacent links, the inner member being rotatable the outer member, a work tool car ried by one of the links, a second work tool mounted the inner member, and a stationary bearing encircling the outer member.

-In testimony whereof I have afiixed signature. u I

PAUL 

